<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>视口的大小</title>
</head>
<body style="height: 2000px;">
    <script>
        //获取视口的宽度『不包括滚动条』
        console.log(document.documentElement.clientWidth);

        //获取视口的宽度『包括滚动条』
        console.log(window.innerWidth);

        //屏幕的宽度  可以用它来获取屏幕的显示分辨率
        console.log(window.screen.width);
        
    </script>
</body>
</html>